docstr: Tests whether the dataset_shard function works correctly with loader_fn.
docstr_tok: ["Tests","whether","the","dataset_shard","function","works","correctly","with","loader_fn","."]
code: def test_dataset_shard_with_loader_fn(self):
      """Tests whether the dataset_shard function works correctly with loader_fn."""
      dset = ray.data.range(100)
      config = AlgorithmConfig().offline_data(
          input_="dataset", input_config={"loader_fn": lambda: dset}
      )
  
      ret_dataset, _ = get_dataset_and_shards(config)
      assert ret_dataset.count() == dset.count()
  
imports: import tempfile
  import os
  from pathlib import Path
  import unittest
  import pytest
  import ray
  from ray.rllib.algorithms.algorithm_config import AlgorithmConfig
  from ray.rllib.offline import IOContext
  from ray.rllib.offline.dataset_reader import DatasetReader, get_dataset_and_shards, _unzip_if_needed
label_desc: Use image node_id 7 for calling the TestDatasetReader obj's underlying member method code with example usage: obj.test_dataset_shard_with_loader_fn() without return types